Digital current controllers applied to the boost power factor correction converter with load variation

This study proposes two digital predictive current controllers applied to the boost power factor correction (PFC) converter able to operate with a load variation up to 600 W. A comparison between them is made to determine which controller presents the best performance and benefit cost ratio. They have in common the possibility of operation in discontinuous, mixed and continuous conduction modes. This operation capability yields several advantages to boost PFC converters with variable loads, as will be discussed. The control laws and the structure of the proposed controllers are shown in detail. Implementation issues (hardware and software) are also shown. Experimental results point out that high converter power factor and low input current total harmonic distortion (THD) are achieved over the entire output power range using both current controllers, with a low implementation cost.